The present invention relates generally to a self-contained excavation device, and particularly to an improved pressurized fluid excavator and anchor apparatus for a beach umbrella.
A self-contained excavation device, with a means for storing and pressurizing the drilling fluid, was disclosed in U.S. Pat. No. 6,050,352 as a beach umbrella anchor. Field testing of the beach umbrella anchor in the above-described patent has suggested additional improvements to that original design.
In general, beach umbrellas must withstand modest wind loads without laterally overturning or vertically pulling out of the formation, which typically comprises beach sand. Overturned beach umbrellas may cause a safety hazard to nearby beach goers. Proper depth of insertion of the umbrella pole into the sand is a critical factor of a successful beach umbrella site. Insertion to a nominal depth of one foot usually provides adequate lateral resistance to wind loads, but vertical pullout is controlled by friction between the pole and the surrounding formation, as well as by the type of sand, the moisture content, and relative compaction of the formation immediately adjacent to the pole. Insertion of the pole into dry sand, where only the bottom end is embedded into wet sand, helps prevent overturning, but not vertical pullout. Also, the diameter of the umbrella pole helps determine both vertical pullout and overturning resistance. During excavation, minor shell layers are occasionally encountered which the blunt-ended bottom of the pole cannot penetrate, thereby preventing easy insertion of the pole to proper depth.
In addition to the above problems relating to anchoring the beach umbrella excavator at a proper depth, additional problems have been identified relating to the pressurized drilling fluid chamber. One such problem relates to the potential of overpressurizing the chamber by excessive use of the air pump. An additional concern relates to the need for frequent maintenance of the fluid release valve. Refilling the apparatus from ocean or lakes can allow debris and sand to accumulate in the lower chamber where drilling fluid is stored, and eventually lodge in the valve, causing leaks and inconsistent valve operation.
It is with regard to this background information that the improvements available from the present invention have evolved.
One object of the present invention is to provide an improved, self-contained excavation/anchor apparatus which not only uses an internal fluid reservoir to ease the excavating process but also provides an enhanced anchoring ability once the excavation is complete.
Another object of the present invention is to provide an improved, self-contained excavation/anchor apparatus which allows for easy removal of the anchor from the excavated hole.
A further object of the present invention is to provide a self-contained excavation/anchor apparatus with an improved cutting head that dislodge hidden obstructions (such as shells) without requiring the cutting head the cut through such obstructions.
Another object of the present invention is to provide a self-contained excavation/anchor apparatus having an improved pressurization system for an internal supply of drilling fluid which prevents overpressurization of the drilling fluid.
A further object of the present invention is to provide a self-contained excavation/anchor apparatus having an improved delivery system for an internal supply of drilling fluid which prevents debris within the drilling fluid from clogging the delivery system and interfering with the operation of the excavation apparatus.
In one preferred embodiment, the apparatus of the present invention includes a cutting head at one end of an excavation tube where the excavation tube includes at least one recess in its outer surface. The recess forms an anchor shelf for engaging the surrounding formation material. Compaction of the formation material (by the drilling fluid applied during the excavation process) forms a connection between the surrounding formation and the anchor shelf which prevents the cutting head from being easily pulled from the excavated hole. The recesses also define anchor sweep faces adjacent the anchor shelf for sweeping or severing the connection between the anchor shelf and the surrounding formation.
Another embodiment of the present invention includes a stepped cutting head forming a plurality of sweep faces to assist in clearing shell layers and other minor obstructions away from the cutting edge during excavation.
A further embodiment of the present invention includes a self-contained excavation/anchor apparatus having a check valve for limiting the pressure that can be applied to a reservoir of drilling fluid carried within the apparatus. Furthermore, because the drilling fluid may often include debris (such as when the apparatus is refilled from ocean water), a self-cleaning valve is employed to prevent such debris from clogging the fluid delivery system and causing the apparatus to malfunction.
In one preferred embodiment, the apparatus comprises an excavator/anchor for a beach umbrella where an end of the apparatus opposite the cutting head is adapted to receive and hold an upper pole of the beach umbrella. Of course, a variety of other objects may make use of the present invention, such as anchoring torches, signs, etc. within the sand or loose soil. Furthermore, the apparatus of the present invention may be beneficially used wherever one needs to create relatively shallow excavations (e.g., gardening or underground utility probes).
A method of using the excavation/anchor apparatus is also disclosed.
A more complete appreciation of the present invention and its scope can be obtained from understanding the accompanying drawing, which is briefly summarized below, the following detailed description of presently preferred embodiments of the invention, and the appended claims.